Curing of polymers of substituted monoolefinic hydrocarbons with polyvalent metal compounds



' above.

Patented Feb. 18, 1947 CURING OF POLYMERS OF SUBSTITUTED MONOOLEFINICHYDROCARBONS WITH. POLYVALENT METAL COMPOUNDS Ambrose McAlevy, Daniel E.Strain, and Franklin" S. Chance, Jr., Wilmington, DeL, assgnors to E. 1.du Pont de Nemonrs & Company, Wilmington, Del., a corporation ofDelaware No Drawing. Application October 27, 1943, Serial No. 507,874

This invention relates to a process for preparing synthetic elastomersand more particularly to their preparation by the curing ofsubstantially saturated high molecular weight polymers from monooleflniccompounds containing a plurality of substituent groups.

The curing of elastomers, including natural rubber, buna rubber,chloroprene rubber, polybutadiene, isobutylene-butadiene' interpolymerand the like, has been accomplished hitherto by the use of sulfurizingagents such as sulfur or sulfur chloride. Hitherto, an elastomer couldbe vulcanized if it could be sulfurized, thatis, if it containedolefinic unsaturation which could react with either sulfur r sulfurchloride. Also, chlorinated compounds could be sulfurized by reac-. tionwith metal polysulfides, thereby producing 22 cla m. (Cl. zen-2'1")products which had certain properties similar to those of rubber. i

All of the rubber-like products which have been prepared by means of thesulfurizing reaction have serious limitations. Natural rubber, and thevarious diene interpolymers, all contain olefinic unsaturationbefore-and after curing. This results in pooraging properties.Furthermore, the maximum tensile strength of sulfurized elastomers israrely better than 4000-4500 pounds per square inch, which isapproximately the tensile strength of best quality tire tread stockrubber. A still more serious limitation on the sulfurized elastomers istheir poor heat resistance. It is generally known that vulcanizednatural rubber, if heated to temperatures above the optimumvulcanization temperature will degrade or depolymerize, to give products,of decreasing strength and lower softening temperature.

It is an object of this invention to provide a vulcanized elastomerwhich does not have the limitations of the sulfurized elastomersdescribed 1 A further object of the invention is to provide valuableproducts from the polymers of substituted olefinic hydrocarbons whichprior to polymerization contain a single ethylenic linkage. Anotherobject of the invention is to provide a procedure whereby polymers ofolefinic hydrocarbons containing plasticizing as well as substituentsalt-forming groups are cured. Yet another object is ,to provide curedhalogenated polymers from olefinic hydrocarbons, which prior topolymerization contained a single ethylenic linkage and which polymerslikewise contain substituent salt-forming groups. Other objects andadvantages of the invention will be morejfully particularizedhereinafter. i

. I 2 In accord with its simplest aspects, the invention may becharacterized as involvingthe curing of polymers which prior topolymerization contain a monoethylenic linkage; their curing being madepossible because of substituent groups which are attached to thepolymeric chain and in addition the invention provides cured elastomershaving many properties equalto and some superior to those of natural andsynthetic rubbers.

The two classes of substituents used in accord with the process of theinvention are, for clarity and simplicity in their consideration,character- .zed as'flrst class and second class substituents; themembers of the first class impart elastic properties to the finalproduct and the members of the second class or salt-forming substituentsimpart curing properties to the polymer. I

The simplest member ofthe first class that aids in inducing elasticityis a halogen group, which may be formed in accord with the processdescribed inU. S. Patent No. 2,183.558. issued to E. W. Fawcett, or byany'other suitable process for obtaining halogenated polymers of theoleflnic hydrocarbons such as ethylene, propylene, isobutylene, andsimilar hydrocarbons. These poly.- mers may likewise be obtaineddirectly bythe polymerization of vinyl chloride, vinyl chloracetate,vinylidene chloride (preferably interpolymerized with knowninterpolymerlzing agents to give the desired chlorinecontent), thehalogena tion of a polyvinyl alcohol or by any other suitable processwhereby a polymer is obtained conthe resulting product.

taining the hereinafter specified amount of halogen such as chlorinerequired to give elasticity to Other substituents will likewise impartelasticity to the ultimate prodnot and as examplesof these may beindicated hydrocarbon side-chain groups such as methyl, ethyl, benzyl;acyloxy groups such as, for example, acetate, propionate; isobutyrate,and the like. Polymers containing these groups areusually, but notnecessarily, formed by polymerizing a monomeric compound containing thesubstituent groupsrather than by inserting the groups by chemical meansafter the polymer has been formed, For example, compounds containing theacetate group are provided by copolymerlzation of vinyl, acetate orvinylchloracetate with ethylene, the propionate group by'the copolymerlzationof vinyl propionate with ethylene, and so the sulfur-bearing substituentbutylene, styrene, and the'like with the hydrocarbon containing amonoethylenic linkage,

Preparations of several ethylene copolymers whichcontain groups of thefirst class are disclosed in the following copending applications of W.E. Hanford: S. "N. 417,476, filed November 1, 1941; S. N. 417,477, filedNovember 1, 1941, and

8. N, 446,116, filed June 6, 1'942.

Substituents of the second class that impart curing properties areprovided by reacting the monoolefinic hydrocarbon or its substitutionproducts, prior, during or subsequent to polymerbe used tofmean that thepolymer treated has imization with a compound capable of introducingsalt forming groups. This substituent may be introduced by subjectingthe polymershaving substltuents of the first class to treatment, undersuitable conditions with sulfonating, phosphating, chlorosulfonating,chlorophosphonating, phosphonating, chlorocarboxylating, orcarboxylating I agents, or agents that will introduce a hydrogenAlternatively. this substituent may be presentin the monomer prior tovulcanization, as for example in the preparation of isobutylene-methylmethacrylic acid interpolymers. Both groups may be introduced into anolefin polymer simultaneously. For example, the chlorosulfonyl group maybe introduced by the process disclosed in U. S. Patent No. 2,212,786,issued to D. M. McQueen, which provides products exceptionally welladapted for the preparation of superior products by curing in accordwith the invention. The phosphonic groups may be introduced bychlorination of a polymer of ethylene, in carbon tetrachloride whichcontains phosphorus' oirychloride, while the chlorcarboxyl groups maybe'lntroduced by chlorination of polythene'in the presence of phosgene,or alternatively by the chlorcarboxylation method of Kharasch and Brown,described in the Journal of the American'Chemical Society, vol. 62(1940, page 454), and their U. S. Patent No, 2,326,229.

A useful method for introducing a substituent of the second class into asaturated rubbery resin like chloropolythene or polyisobutylene is todissolve'or suspend the resin incarbon tetrachloride, and, whilestirring the solution or suspension very rapidly, to add a suspension ofoleum or chlorosulfonic acid in carbon tetrachloride thereto. After thereaction, the solvent and unreacted acid are removed from the product bysteaming. In a similar manner, polythene may be treated withchlorosulfonic acid to introduce this .substituent, and subsequently thesulfonated polythene may be chlorinated in carbon tetrachloride solutionto introduce the substituent of the first class. Furthermore, polythenemay be chlorinated in carbon tetrachloride solution in the presence ofsulfur, a sulfur halide or asulfur o'irychloride, and the resultingrubbery resin may be steamed to cause verted toa second class group.

The product prepared by any of the methods described above whichcontains at least one'of the first and at least one of the second classof groups, and which is'basicallya polymer-of a. monoolefinichydrocarbon can be cured to give valuable elastomers. In thisapplication and the claims appended thereto the term ,curing"wil1 groupto be con;-'

parted to it improved properties especially with respect to greatersolvent resistance, higher tacking point, less plastic flow, improvedelasticity and increased tensile strength.

The amount of the first class substituent to be used will be determinedin large measure by the degree of elasticity desired in the finalproduct,

and in the nature of the substituent groups.

When these substituent groups on a polymethylene chain are chlorinegroups, rubbery vulcanizates having optimum elastic properties areobtained when the ratio of substituent chlorine atoms to carbon in thechain isin the range be-x tween ,1 to 4 and 1 to 8. More broadlyspeaking and on a percentage basis they may contain from to 45%chlorine. Similarly when the first class substituent is the acetategroup, the optimum ratio of acetat to carbon atoms in the chain is inthe range between 1 to 6 and 1 to 14. While we do not wish to be boundby any theory, it appears that groups which are less polar, such asthe'methyl group, must be more numerous along the chain to. produce thedesired elastic effeet, for, whatever the cause, the optimum ratio ofmethyl groups, substituted along a polymethylene chain, to carbon atomsin the chain is about More than one variety of the first class groupmaybe present in the resin. For example, methyl groups andchlorinejgroups or acetate groups and chlorine groups may be presentsimultaneously. Under such circumstances, the frequence of substitutionof the various first class groups along the chain is preferablyininverse proportion to their relative powers to produce the desiredelastic efiect individually as described above. Thus, a substitutedpolymethylene which contained one acetate group per twenty-sixcarbon'atoms in the chain and one chlorine group per seven carbon atomsin the chain was found to have a suitable amount for the preparation ofhigh quality elastomers. While the ratio of the number vof carbon atomsin the chain to the number of substituent first class groups is givenabove interms of'optimum ratios it should be pointed out that elastomersmay be made in which the ratio of the number of carbon atoms in thechain to the number of substituted groups is outside of the optimumrange. In fact there is a gradation in the degree of rubberiness as theratio varies from the optimum range to a lesser degree of substitution,until finally the properties become 7 those of polyethylene which is arelatively stiiI,

slightly elastic resin, furthermore there is a 1 class substituted groupis polar, like the chlorine or acetate group. Nevertheless, theprinciple of this invention may be applied over the entire range ofdegree of substitution of a polymethylene chain by groups of this class,provided second class, salt-forming groups are also present.

The optimum number of second class groups that promote curingisdetermined by the molecular weight of the elastomer and the nature ofthe rubbery product desired. In general, the optimum average number ofsalt-forming groups per molecule is'between 2 and 50 for polymers havingfrom 600 to 5000 carbon atoms in the chain, and is inverselyproportional to the numthe absence of free sulfur. these agents whichgivebest results are, per 100 parts of substituted polymer: oxide of dior poly-- valent metal, 2 to 60 parts preferably' 10 to 20 5 ber 01'carbon atoms in the chain. A suitable average number for a chaincontaining 1000 carhereinafter disclosed.

Thus, for chlorosulfonated polymers of ethylene prepared in accord withthe process described in U. S. Patent 2,212,786 from polythene which hasa molecular weight of 14,000, and which contains 30% chlorine,the'optimum range of comblnedsulfur content for the'preparation ofelastomers in accordance with this invention is 0.4 to 3.0%. When thedegree of salt-forming substitution is less than is indicated by 0.4%

sulfur, a large part of the elastomer is unvulcanizable, as evidenced bythe quality of the total vulcanizate, i. e.-it lacks snap, is partlysoluble in organic solvents and otherwise displays'the behavior ofelastomers which possess. large pro- 4 portion of organic'filler.

The curing operation is best conducted by compounding the substitutedpolymer witha vulcanization mix containing an oxide of a polyvalentmetal and other curing aids herein described, followed by subjecting themix to heat and pressure. The heating may, if desired,'be appliedsubse-. quently or simultaneously with the mixing. I

The metal oxide preferred for use in the vulcanization mix is litharge,-although good results are also obtained with magnesia, zinc oxide, red

lead and barium oxide and other polyvalent metal oxides, particularlydivalent metal oxides. Equivalents of the'oxides in this invention arethe 'hydroxides, and the salts thereof with weak acids such as zincstearate, lead abietate,-magnesium '1 adipate, and calcium carbonate. Ofthese salts, the lead and zinc saltsof high molecular weight "weak acidsparticularly naphthenic, 'abietic and ste'aric are most suitable.

In addition to the metal oxide, the vulcanization mix may contain a weakmonobaslc or polybasic acid of high molecular weight, such as stearicacid or rosin.

pressure.

be employed in quantity equivalent tofrom 0 to 100 parts per 100 partsof elastomer, but preferably from 0 to-20 parts per 100 parts ofelastomer.

The unmixed elastomers containing elastomer groups and salt-forminggroups "as above "described may be converted in the absence of metaloxide or vulcanization aid, to products of lesser solubility andincreased resilience by heating to 100 to 300 C., but the products thusobtained often lack strength, and are inferior to the'c'ured productsobtained from the compounded elas tomers.

The substituted polymers are compounded in preparation for curing bymixing them with the desired amounts of compounding ingredients onregular rubber millrolls which compounding may be effected at roomtemperature or above. The product is then cured by heating at atemperature of 100 C. to 160 C. for a period in the order of 10' to 60minutes, "under a pressure 01' from about 15 to 500 pounds per squareinch. If it be desired to prepare shaped articles the milled product iscured in a suitable heated mold under Usually there is evidence ofcuring as the temperature approaches approximately 60 C., althoughtemperatures "of 100 C. or slightly higher are sometimes required. Thereis generally no need for temperatures in excess of 180 C., andtemperatures in excess of 300 C. cause from Example 1, both in regardto' length and Small amounts of antioxidants and/0r acceler'asulfate,.kaolinjdiatomaceous earth,- powdered talc, titanium dioxide, andcalcium sulfatemay be used. Sulfur may also be included in thevulcanization mix, but it is generally omitted since the vulcanizationreaction takes place readily in parts and with litharg especially 30 toparts; rosin, or equivalent, 0 to 30 parts, preferablyb to 10 parts;antioxidant, 0.0 to 3.0 parts; preferably 0.5 to'2.0 parts;accelerator,,0 to8 parts,

The quantities of temperature oftreatment, and may be carried out in amold in the presence or in the absence of external pressure, as forexample, in the'preparation of spongy articles where a blowing agent isemployed. I

As a result of the heat and pressure treatment a pronounced reactionoccurs in each instance yielding a product which has propertiesresembling the properties of vulcanized rubber. I These I cured productsdiffer markedly from the uncured 'elastomer in a number of respectsincluding considerably increased resistance to cold flow, and

increased tendency to return to original dimensions after deformation bystress. I I 7 Examples will now be given illustrating preierredembodiments of the invention in which 'parts are'by weight unlessotherwise indicated.

The following list indicates the nature of certain ingredients referredto in the examples; AgeRite a Alba, a trade name for hydroquinonemonobenzyl ether; Captax, 'mercaptobenzothiazole, marpreferably 1 to 5parts; inorganic fillers-organic fillers or reenforcing agents 0 to 500parts, preferably 0 to 30 parts. I I I For certain special applications,in which products having reduced stiffness are required, or-

ganic fillers or extenders may be added to the vent while 24.9 partschlorine and 6.7 parts-sulfur vulcanization mix. These include asphalt,poly-- isobutylene, Naftolens (which are products derived from the acidsludge 'in. ol1 refining and marketed by Wilmington ChemicalCorporation), factice, pine tar, and'Flexalin (diethylene glycolabietate, marketed by Hercules Powder Company). -These organic fillersor extenders may *keted by R. T. Vanderbilt C03 Pexite I, a refinedrosin marketed by Hercules Powder Company.

I Example 1.-'A solution containing 25 parts eth- I :ylenepolymenwhichhas a molecular .weight of 21000-25900, and 670 parts carbontetrachloride is stirred rapidly at'the boiling pointfOf the soldioxideare bubbled'into the mixture. A ty'p eJ-h mercuryvapor lamp is used toirradiate'th'e reactants. After 21 minutes, during which tirne thetemperatureis allowed to drop to 40 C.,"t he reaction is complete.Removal of the solvent is accomplished by steam distillation, followingwhich the rubbery residue is washed with water a to remove water-solubleacids. I I I I milled for 45 minutes on a rubber mill at -130 Theproduct is means of a rubber mill.

. inch at 300% elongation.

1 i of resin.

C. so as to obtain a dry rubbery mass, which contains 27.6% combinedchlorine and 2.76% com- 1 Example 2.Twe'nty-five parts of an ethylenepolymer having a molecular weight of 12,000- 15,000 is dissolved in 800;parts of carbon tetr'achloride in a Pyrex vessel at 77 C. To thesolution is added 15 parts sulfuric oxychloride, and the mixture isstirred rapidly while being irradiated by means of a 300-watt tungstenfilament incandescent lamp. .Under these reac- .tion conditions 40.5parts of chlorine are introduced over a period of one hour. The resinousproduct isthen precipitated by adding 1600 parts of methanol, and theprecipitate is washed several times with methanol. Finally the productisfreed of volatile matter by drying in a, vacuum oven at 50 'C. Thisgives a, rather stiff rubbery resin which contains 47.0%. chlorine and0.56% sulfur. To 100 parts of this resin is added 5 parts wood rosin, 2parts phenyl betanaphthyl .amine, 1 part sulfur, parts zinc oxide. Theseingredients are milled togetheron a rubber mill,

and the mixture is then placed inv a moldv and heated at 125 C. for 60minutes. The resultin rubber-like vulcanizate has a tensile strength of3100 pounds per'square inch and an elongation of 450% at thebreak-point. After the break, the vulcanizate retains a residualelongation of 25%.

Example 3.-A streamofchlorine (1.05 parts per minute) is conducted intoa rapidly stirred solution containing 50 parts of ethylene polymer(having a molecular weight of 12,000 to 15,000

in 1600 parts of carbon tetrachloride, and 10 parts of thionyl chloride.Temperature is main tained at 77 C.. After one hour the chlorination isstopped and the solvent is removed from the mixture bysteamdistillation. The product is washed several times with warm water,then is milled for 35 minutes at 70 C. on the rubber mill. The rubberyproduct which results is shown by analysis to contain 34.1% chlorine,and 1.14%- sulfur. A film of this rubbery material is heated at 120 C.for 24 hours. A dark, tough, elastic film which resembles vulcanizedrubber is thus obtained.

Example 4.-A sample of chlorosulfonated ethylene polymer prepared by thegeneral method described in U. S. Patent No. 2,212,786, I from polythenehaving a, molecular weight of 10,000, contains 34.9% chlorine and 0.4%sulfur. This v analysis corresponds to. 4.7 carbon atoms per chlorinegroup, and 372 carbonatoms per sulfonic-group, or 1.9 sulfonic groupsper molecule Since this sulfur content is a few tenths of a percentlower than is required for preparation of the best .quality elastomers,the sample is dissolved in carbon tetrachloride .(125 partschlorosulfonated polythene per 1400 parts carbon tetrachloride), andi50parts sulfuric 'oxychloride are added. The mixture is heated for 2 hoursat 76 C. in the presence of diffuse daylight. The solvent is thenremoved by steam dis- I tillation and the residual resin is washed withwarm water until free of soluble acid. Finally the resin is dried on therubber mill. The product contains 34.0% chlorine and 0.76% sulfur. To100 parts of thisrubbery product are added 2 parts-phenyl beta naphthylamine, 15 parts of wood rosin, and 5 parts of magnesia. This mixture,after being milled on the. rubber mill, is cured for 60 minutes at 155C. The resulting cured elastomer has a tensile strength of 2400 poundsper square inch and an elongation of 600% at the break-point. I

Example 5.--A solution containing parts polyisobutylene (molecularweight, 140,000) in 600 parts by volume carbon bisulfide is stirred veryrapidly while a suspension of 2 parts chlorosule ionic acid in 50 partsby volume carbon bisulfide' is introduced. Temperature is maintained at46 C. After 2.5 hours the solvent is removed by steam "distillation,.and the rubbery product iswashed free of soluble acid with water. Theresin is' then dried on the rubber mill, yielding .'1 part Captax, 10

sulfur dioxide under radiation from a 300-watt product is precip-'v arubbery mass which contains 0.38% combined sulfur. To 100 parts of thismaterial the following ingredients are added: parts channel black, partswood rosin, 40 parts litharge; 5 parts zinc oxide, 6 partsdipentamethylene thiuram tetrasulfide, and 3 parts 'of sulfur. Whentheseingredients are thoroughly mixed the mixture is placed in a mold andvulcanizedfor minutes at 145 -C. The resulting rubbery product has atensile strength, of 850 pounds persquare inch and an elongation of 800%at the break point.

Example 6.-A,solution containing 25 parts of a vinyl chloride-ethylenecopolymer (chlorine.

content, 20%; molecular weight, 20,00.0-'22,000) in .1200 parts ofboiling carbontetrachloride is treated with 15 parts of chlorine and 7parts of tungsten filament lamp. The itated by addition of methanol.After, drying in a vacuum .oven, it is foundv to contain 32.0%

chlorine and 1.26%,sulfur. The productis cured in the manner describedin Example 1 for the curing of chlorosulfonated polythene. The

. product closely resembles cured chlorosulfonated I steam distillingthe solvent and washing several polythene. r

Example ?.Twenty-five parts of an ethylene polymer (molecular weight20,000-25000) are dissolved in a mixture containing 800 parts of carbontetrachloride and 5 parts of phosphorus oxychloride at 77, and to thesolution 43.9 parts of chlorine are added. The product, isolated bytimes with water, is milleddry on the rubber mill. It is an elastic, butrather stiff solid, which analyzes 40.0% chlorine and 0.76% phosphoruscombined as phosphoric'group. This chlorophosphonated polythene ismilled with one half of its weight of magnesia, then heated in a mold at120 C. A mixture of vulcanized'and unvulcanized elastomer results.

Ezample 8.A solution of 25 parts of polyisobutylene (molecular weight140,000) in 800 parts of carbon tetrachloride is rapidly stirred at 35to 40 0., and a mixture containing 2.4 parts chlorine and 4.4 partssulfur dioxide is introduced. The-introduction of these gases requires10 minutes, throughout which time the reaction-mixture is irradiated bymeans of a type H4 -watt mercury ,vapor lamp. The solvent is thereafterremoved by steam distillation, andthe resulting resin isv washed free ofwater-soluble acid. Fi-' dipentamethylenethiuram tetrasulflde, and themixture is milled on the rubber mill. Finally it is .cured in a mold for60 minutes at'135 C.,

yielding a product. which has a tensile strength of 700 pounds persquareinch and an elongation of 800% at the break-point. After the break, thisrubberyproduct snaps back to a residual elongation of 50%.- g

Example 9.An ethylene-vinyl acetate interpolymer which contains 12ethylene units per unit of vinyl acetate, and which has an averagemolecular weight of approximately 20,000 is dissolved in carbontetrachloride, forming a solution which contains 25 parts of theinterpolymer per 800 parts of .the solvent. Into this solution 22 partsof chlorine and 2 parts of sulfur. dioxide are introduced simultaneouslyat 77 while the mixture is being irradiated by means of a type H4100-watt mercury vapor lamp." After 15 minutes the solvent is removedfrom the mixture by steam distillation, and the resulting resin iswashed free of water-soluble acids. This resin is dried on therubber'mill at 90 C. I A tough rubbery product which contained 22.8%chlorine and 1.0%

sulfur is thus obtained. This product prior to curing has atensilestrength of 400 pounds per square inch and an elongation of 1400%at the break point, returning after the break to a residlPexite r, and40 parts or litharge. The mixtur is then curedior 60 minutes at 135 C.The resulting elastomer has a tensile strength of 5000 pounds per squareinch and an elongation of- 400% at break. After the break it retains aresidual elongation of percent. p

Example 12.--100 parts of chlorosulfonated ethylene polymer containing28% chlorine and 1.4% sulfur was compounded with 0.5 part Latac(hexamethyleneammonium hexamethylenedithio-. 'carbamate) 1 part Captax,10 parts rosin and'40 parts litharge and cured 60 minutes at 135 C.

- The tensile strength was 2750 pounds per square 'inch at 425%elongation with recoveryto week at 90 C.,' the compression set wasimproved to 7%. This is an exceptionally good compression set value,comparing to 15% for well cured tread stock rubber using the same testprocedure. A similar composition using only 0.25% Latac \{liS well curedon heating for 3 to 5 minutes at 5 C. 1 Example 13.--100 parts ofchlorosulfonated ethylene polymer containing 30% chlorine and 0.9%sulfur was compounded with 1 part AgeRite Alba, 1 part Captax, 10 partsrosin and parts minium (Pba04) and cured 60 minutes at 155 C. Thetensile strength was 2900 pounds per square inch at 525% elongation withrecovery to 50% residual elongation. This formula gave Example 10.Asolution of 25parts of a chlorinated polymer of ethylene (chlorinecontent,

26%; molecular weight 15,000-18,000) in 800 parts carbon tetrachlorideis very, rapidly stirred while 4.3 parts chlorosulfonic acid isadded'dropwise, this addition requiring about 60 minutes. During thistime the temperature is kept within the range 30-70 C. When the reactionis complete the solvent is removed fromthe dissolved resin by steamdistillation, and the residual rubbery mass is thereafter washed withwater until free of water-soluble acid.. It is then dried on the rubbermill. This gives a product which contains 25.7% chlorine and 0.9%sulfur; combined as sulfonic group. It is cured by compounding with 1part AgeRite Alba, 1 part Captax, 10 parts wood rosin and 40 partslitharge, followed by heating in a mold for 60 minutes at 135 C. Theresulting cured elastomer has a tensile strength of 1500 pounds persquare inch and an elongation of 550% at the break point. I

Example 11.-'One lot of chlorosulfonated ethylene polymer, prepared frompolythene having a molecularweight'of 40,000-45,000 by the generalmethod described in U. S. Patent 2,212,786, has a chlorine content of30% and a value of 50%.

a lower modulus stock with better compression set than when litharge wasused in place of minium. The compression set value was 36% and improvedto 20% on heating 1 week at C. A similar composition with litharge inplace of minium gave an original compression set Example 14.-- parts ofchlorosuifonated ethylene polymer containing 30% chlorine and 0.8%sulfur'was compounded with 0.5 parts diphenyl guanidine, 10. partsmagnesium oxide and 5 parts (NI-10200:, and cured 60 minutes at C. Thevulcanizate had a tensile strength of 1400 pounds per square inch at700% elongation with recovery to 30% elongation. I

Example 15.--A product containing 30% chlorim and 0.3% sulfur wasprepared by chlorinating ethylene polymer (75 parts) at 77 C. incarhon-tetrachloride solution (2400 parts) containing sulfur dichloride(5 parts). This product was isolated from the chlorination mixturebyinjecting steam until all of the solvent had been Example 16.--Asolution of 100 parts ofchlorinated ethylene polymer (40% chlorine), 5parts hydrogen sulfideand 0.5 parts ferric chloride in 800 parts carbontetrachloridewas heated ina closed vessel at 145 to 152 C. for 2 hours.The

resulting. solution was removed from the res-c tion vessel and wasthereafter treated with steam to remove solvent, whereby a rubberyresin'was obtained. After being washed with waterythen dried on therubber mill, this rubbery material contained 42% chlorine, and 0.7%sulfur comi was 1750 pounds per square inch at 400% elon- 11 1 bined ashydrosuiflde. 100 parts of this product was compounded with 0.2partstetramethylthiuramdisulfide, 0.5 I parts diphenyl guanidine, 10'parts zinc oxide, 30 parts channel black and cured 60minutes at 155 C-The tensile strength gation with recovery to 45% Example17.'-Chlo'rinated ethylene polymer (40 parts, 40%. chlorine) was treatedwith- 5 parts ethandithiol in carbon tetrachloride (1600' parts) for 3hours at 75 vC. in the presence of 0.5 parts ofgierric chloridecatalyst. The product, isolated as described in the preceding example,con-- tained 40% chlorine and 7.7% sulfur. 100' parts of this productwas compounded with l'part Altax, 40 parts litharge, and 3 parts rosin,and cured 60 minutes at 175 C. Thetensile strength was 500 pounds persquare inch at 7 5% e1on-" gation with recovery to 25%-residualelongation. ,Nulcanized chlorosulfonated polythene, prepared by themethod disclosed in- Examplell is in certain -respects a superiorelastomer to 'vulcanized natural rubber or hitherto known vulcanizedsynthetic rubbers. For example, in resistance to, elevated temperaturesvulcanized chlorosulfonated polythene is markedly to the sulfurizedelastomers. onstrated this point was carried out as follows: A sample ofhigh quality tread stock natural rubber vulcanizate which'had a tensilestrength of 4000 pounds'per square inch was'stored' in an oven at 90 C.for one week. A sample of chlorosuli'onated polythene vulcanizateprepared by the general method disclosed in Example 11 had a tensilestrength of 4500-"pounds per square inch;

superior A test which dem- I curtains,raincoats, etc.) sponge rubberproducts (arm rests, cushions, sponges,

ball plates, etc.), stationers'goods (typewriter feet, telephone bases,coin mats, cord protectoral etc.), thread, topsand novelties (dolls,molded toys, balls-dog toys, sponge novelties, etc.), ve-' hgleaccessories (top dressing, tires, pedal pads, e.).

The hard rubber like products are-useful as binders for paint brushinsulators and the like.

We claim:

1. A process'for'the preparation of rubber-likecompositions whichcomprises curing at a temperature between 125 and 175. C., and under apressure of from 15 to 500 pounds per square inch for from 15to 60minutes, an intimate mix-, ture of the approximate" composition: 100parts of' chlorosulfonated' polymer of ethylene containing 20m 45%chlorine and from'0.4 to 3% sulfur, one part of mercaptobenzothiazole,one

part of hydroquinone monobenzyl ether, to

12' mats,tops,basebristles, battery cases,

parts of wood" rosin and to 40 parts of litharge.

2. A process for the preparation of rubber-like compositlonspwhichcomprises milling a mixtureof halogenated polymer of ethylene having asalt-forming'constituent other than a halogen with an accelerator and apolyvalent metal oxide,

and subsequently subjecting the resulting milled C.,"'a pressurebetween" 15 and 500 poundsperthis also was stored for one-week at90 C..At

the end of the test period the tensile strength of the naturalrubbervulcanizate had declined to method disclosed in Ex-' 1 product toatemperature between 125 and 175 square inch for between 15 and minutesthe composition containing per 100 parts of'the sub stitutedpolymer from10 to 60 parts of the poly-v valent metal oxide.

3. A rubber-like composition comprising a mixture, cured by heating to atemperature between 60 and 300 0., of a substituted polymer of amonooleflnic hydrocarbon selectedfrom the group consisting of ethylene,propylene and isobutylene --the polymer having 'a' salt-formingsubstituent Since the products of this invention vary from soft, elasticmaterials to hard, horny substances resembling hard rubber, and sincethey can be prepared in any desired shape by molding, they are useful innumerous fields where their pli-- ability, solvent' resistance,nonthermoplasticity,

or rubber properties make them applicable.

pliable compositions are Among the uses for the bathing apparel (belts,caps, capes, etc.), dental goods (dentaldams), drug and surgicalsupplies I (sheeting, tubing, teething rings, nipples, ice bags, etc.),flooring (floor, mats, stair treads),

footwear (rubbers, heels, taps, impregnated soles,

etc.) household items (jar rings, bottle caps, but! tons, coasters, flyswatters, wedges, sink stoppers, aprons, gloves, kneeling pads, ashtrays, mats,

plate wipers, etc.), insulated wire and cable,

laboratory supplies (tubing, stoppers, aprons); coated fabrics, latexproducts (can closures,.jarl rings, etc.), mechanical goods (belting,hose. mountings, gaskets, valve discs rolls, washers,

grommets, auto mats, pedal rubbers, tires for toys, tank linings,windshield wipers, etc.),:

proofed goods (auto fabrics, crib sheets, shower other than ahalogen'and a substituent selected from the group consisting of halogen.hydrocarbod and. acyloxy groups, the combination containing per parts ofthesubstituted polymer1 from 10 to 60 parts of a polyvalent metalcompoundselected from the group consisting of polyvalent metal oxidesand hydroxides. 4

4. A rubber-like composition comprising a halogenated polymer ofethylene having a saltforming substituent other than a halogen, the

composition containing per 100 parts oiithe sub-- stituted polymer from10 to 60 parts of a polyvalent metal compound selected from the groupconsisting of polyvalent metal oxides and poly-- polyvalent metalvalent. metal hydroxides, the composition having,

been cured by heatingto a temperature between 60 and 300 C.

5. .A rubber-like composition comprisinga chlorinated polymer ofethylene having a salt-' forming substituent other than a halogen, the

composition containing per 100 parts of the sub'-' stituted polymer from10 to 60 parts oi apolyvalent metal compound selected from the groupconsisting ofpolyvalent metal oxides and polyvalent metal hydroxides,the composition having been cured by heating toa temperature between 60and 300 C.

6. A rubber-like composition comprising a substituted polymer ofethylene having a hydrocarbon substituent and a salt-forming substituentother than a halogen the composition containing per 100 parts of thesubstituted polymer'from 10 to 60 parts of apolyvalent'metal compound,

' selected from the groupconsisting of polyvalent metal oxides andpolyvalent metal hydroxides, the composition having been cured byheating to a temperaturebetween 60 and 300' C.

7. A rubber-like composition comprising a substituted polymer ofethylene having an acyloxy 'substituent and a salt-forming subst'ituentother composition containing per 100 parts of the substituted polymerfrom 10 to 60 parts of a polyvalent metal oxide, the composition havingbeen cured by heating to a. temperature between 60 and 300 C.

9. A rubber-like composition comprising stearic acid and a chlorinatedpolymer of ethylene having a salt-forming substituent other than a.-halogen "the composition containing P 100 Parts of the substitutedpolymer from 10 to 60 parts ot'a polyvalent metal oxide, the compositionhaving been cured by heating to a temperature between 60 and 10. Arubber-like composition comprising a mixture, cured by heating to atemperature between 60 and 300 C.,of a halogenated polymer of ethylenethat contains the substituent group SonYm in which S is sulfur, O isoxygen, Y is a halogen, n is a symbol from 1 to 3, and m is a numberfrom 1 to 2, the composition containing per 100 parts of the substitutedpolymer from 10 to 60 parts of a polyvalent metal compound selected fromthe group consisting of polyvalent metal oxides and polyvalent metalhydroxides.

11. A rubber-like composition comprising a mixture cured by heating to atemperature between 60 and 300 C., of rosin and a halogenated polymer ofethylene that contains the substituent group SOnYm, inwhich S, issulfur, is oxygen,

V 14 to 8 parts of an acceleratorper 100 halogenated polymer oi ethylenethat. contains the 'substituent group BoaYn, in which 8 is sulfur, 015oxygen, Y is a halogen, n is a symbol from to 3, and m is a numeral from1 to 2.

15. A rubber-like composition comprising a mixture, cured by heating toa temperature'between 60 and 300 0., containing from to parts oflitharge, from 5 to 10 parts of rosin, from 0.5 to 2 parts of anantioxidant, and from 1 to 5 parts of an accelerator per 100 parts of ahalogenated polymer of ethylene that contains the substituent groupSOnYm, in which 8 is sulfur, O

is oxygen, Y is a halogen, n is a symbol from 1 to 3,'and m is a numeralfrom 1 to 2.

16. A rubber-like composition comprising a mixture, cured by heating toa temperature between 60 and 300 C., of a polymer of ethylene which hasbeen combined with chlorine andsulfur dioxide, the compositioncontaining per 100 parts of the substituted polymer from 10 to 60 partsof a polyvalent metal compound selected from the group consisting ofpolyvalent metal oxides and polyvalent metal hydroxides.

17. A rubber-like composition comprising a mixture, cured by heating toa temperature between 60 and 300 C., of a polyvalent metal compound anda chlorosulfonated polymer of ethylene, the composition containing per100 parts of Y is a halogen, n is a symbol from 1 to 3; and m is anumeral from 1 to 2, the composition containing per'100 parts of thesubstituted polymer from ,10 to 60 parts of a polyvalent metal oxide.

12. A rubber-like composition comprising a mixture, cured by'heating toa temperature between 60 and 300 C., of rosin, an antioxidant and ahalogenated polymer of ethylene that contains the substituentgroup'SOn'Yt in which S is sulfur, 0 is oxygen, Y a halogen, n is a symbolfrom 1 to 3,'and m is a numeral from 1 to 2, the composition containingperl00 parts of the subvalent metal oxide.

13. A rubber-like composition comprising a mixture, cured by heating toa temperature bestituted polymer from 10 to parts of 'a poly-,

the substituted polymer from 10 to 60 parts of the polyvalent metalcompound selected from the group consisting of polyvalent metal oxidesand polyvalent metal hydroxides. p

18. A rubber-like composition comprising a mixture, cured by heating toa temperature between 60 and 300 C., of a polyvalent metal oxide and apolymer of ethylene containing from 20 to 45% combined chlorine and from0.4 to 3% of combined sulfur, the composition containing per 100 partsof the substituted polymer from 10 to 60 parts of the polyvalent metaloxide. 19. A rubber-like composition comprising a mixture, cured byheating to a temperature between 60 and 300 C., of a polyvalent metaloxide and a polymer of ethylene containing 30% combined chlorine and0.6% combined sulfur, the composition containing per 100 parts of thesubstituted polymer from 10 to 60 parts of the polyvalent metal oxide.

20. A rubber-like composition which comprises a halogenated polymer ofethylene that contains,

combined phosphorus, the composition containing per 100 parts of thesubstituted polymer from 1 0- to 60 parts of a polyvalent metal compoundselected from the group consisting of polyvalent metal oxides andpolyvalent metal hydroxides, the composition having been cured byheating to a temperature between 60 and 300 C.

.21. A process which comprises heat-curing at a temperature between 100and 175 C., a substituted polymer of a monooleflnic hydrocarbon tween 60and 300 C., of rosin, an antioxidant, an

accelerator and a halogenated polymer of ethylene that contains thesubstituent group SOsYm,

in which 8 is sulfur, Ois oxygen, Y is a halogen,

n is a symbol from 1 to 3, and m is a numeral from 1 to 2, thecomposition containing per 100 parts of the substituted polymer from 10to 60 parts of a polyvalent metal oxide.

parts of a polyvalent metal oxide, up to 30 parts g of rosin, up to 3parts of an antioxidant, and up is-eifectedunder a pressure of between15 and selected from the group consisting of ethylene, propylene, andisobutylene the polymer having a salt-forming substituent other than ahalogen and a substituent selected from the group consisting of halogen,hydrocarbon and acyloxy groups,

rosin, an accelerator and an antioxidant, the composition containing perparts of the substi-- tuted polymer from 10 to 60 parts of polyvalentmetal compound selected from the group consisting of polyvalent metaloxides and polyvalent metal hydroxides. I

22. The process'of claim 21 in which the curing parts 01s file or thispatent:

k l5 7 500 ounds r square Inch forfrombto 60 minutes. pe Itmrmns'mmsmmnws H i 1.gmnarevoslgl?lgtcMZ-EVY; Number I Name I DateANIEL TRAIN 2 2 M ,1 FRANKIJN acmmcm, J11. a cqueen 27 FOREIGN PATENTS vREFERENCES-CITED Number Country Date The following references are ofrejcord 1n :the 545,500 -Br1t1sh May 2'1, 1942

